1. Field of the Invention
The present invention relates to a stopper for closing a medical system, to a method for closing a medical system, and to the medical system itself, closed with the stopper of the invention.
2. Description of the Background Art
Medical systems such as medical bags are used in their millions in medicine and serve for the storing of blood or infusion solutions. For this purpose they must be completely sterile, which is typically achieved by heating to at least 100° C., more particularly to around 121° C. Furthermore, a bag of this kind must be able to be produced easily, cheaply, and in an automatic production operation, and be disposable after use on account of its low value.
Typical medical bags are disclosed in U.S. Pat. No. 4,516,977, which is herein incorporated by reference. That publication discloses bags made of plastics materials based on polyolefins, including those based on polyethylene, polypropylene, and polybutylene. Besides these homopolymers, plastics materials are specified that constitute substituted olefins, carrying, for example, methyl, ethyl, vinyl or halogen atom substituents. Copolymers or blends of such materials are also proposed therein. Cited as being particularly preferred for the bag are polyethylenes of medium to high density, high molecular weight, and narrow molecular weight distribution. In order that the contents of the bags can be run out or else that the bags can be filled, insert pieces, for example, are used, which allow access to the interior of the bag.
Such insert pieces are already known in various forms and are described in, for example, DE 33 05 365 C2 and DE 196 34 944 C1, which are both herein incorporated by reference. To fill the bags, generally, two production methods are used. In one case, the medical bags may first be filled with the fluid in question, and the insert pieces are welded into the bag subsequently, Le., after the filling operation, with the bag being closed completely at the same time. The other known case involves the integration of the respective insert piece into the medical bag prior to the filling operation, with filling being accomplished subsequently. For this purpose, generally, a separate filling opening is used, which is formed by a gap in the edge welding of the film bag and which is sealed or welded after filling.
A further option for filling the medical bag and/or removing its contents is supplied by connections to which tubes can be connected, and by openings which are closed with a pierceable stopper. These systems are usually welded to the bag material, and are usually costly and complicated to produce.